U.S. patent number 11,456,669 [Application Number 16/988,006] was granted by the patent office on 2022-09-27 for voltage supply to a load and battery.
This patent grant is currently assigned to Apple Inc.. The grantee listed for this patent is Apple Inc.. Invention is credited to Jeffrey M. Alves, Philip Juang, Kisun Lee, Yehonatan Perez, Peng Wu.
United States Patent |
11,456,669 |
Alves , et al. |
September 27, 2022 |
Voltage supply to a load and battery
Abstract
Implementations described and claimed herein provide systems and
methods for supplying voltage to a load and battery. In one
implementation, a first regulated DC-to-DC converter is
electrically connected to a first energy source to down convert a
first voltage supplied by the first energy source. A load is
electrically connected to the first regulated DC-to-DC converter to
receive the down converted first voltage. A second regulated
DC-to-DC converter is electrically connected to the first regulated
DC-to-DC converter to regulate the down converted first voltage to
a second voltage. A second power source is electrically connected
to the second regulated DC-to-DC converter to charge the second
power source using the second voltage, and the second power source
is switchably connectable to the load.
Inventors: |
Alves; Jeffrey M. (Pleasanton,
CA), Wu; Peng (Sunnyvale, CA), Perez; Yehonatan
(Menlo Park, CA), Lee; Kisun (Pleasanton, CA), Juang;
Philip (Mountain View, CA) |
Applicant: |
Name |
City |
State |
Country |
Type |
Apple Inc. |
Cupertino |
CA |
US |
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Assignee: |
Apple Inc. (Cupertino,
CA)
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Family
ID: |
1000006583820 |
Appl.
No.: |
16/988,006 |
Filed: |
August 7, 2020 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20200366205 A1 |
Nov 19, 2020 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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16012118 |
Jun 19, 2018 |
10737586 |
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15764438 |
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PCT/US2016/053093 |
Sep 22, 2016 |
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62235129 |
Sep 30, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B60L
58/20 (20190201); H02M 3/1582 (20130101); H02M
1/007 (20210501); B60L 2210/12 (20130101); B60L
2210/14 (20130101) |
Current International
Class: |
H02M
3/158 (20060101); B60L 58/20 (20190101); H02M
1/00 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1717938 |
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Nov 2006 |
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EP |
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2193954 |
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Jun 2010 |
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EP |
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2896744 |
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Aug 2007 |
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FR |
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Primary Examiner: De Leon Domenech; Rafael O
Attorney, Agent or Firm: BakerHostetler
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION
This patent application is a Continuation-in-part of U.S.
Non-provisional patent application Ser. No. 16/012,118, entitled
"Converter Architecture," filed Jun. 19, 2018, which is a
continuation of U.S. Non-provisional patent application Ser. No.
15/764,468, entitled "Converter Architecture," filed Mar. 29, 2018,
which is a 371 of PCT Patent Application No. PCT/US2016/053093,
filed Sep. 22, 2016, entitled "Converter Architecture," which
claims priority to U.S. Provisional Patent Application No.
62/235,129, entitled "Converter Architecture" and filed on Sep. 30,
2015, the disclosures of which are specifically incorporated by
reference in their entireties herein.
Claims
What is claimed is:
1. An apparatus comprising: a first regulated DC-to-DC converter
electrically connected to a first energy source to down convert a
first voltage supplied by the first energy source into a down
converted first voltage, wherein the first energy source is
connected in series with the first regulated DC-to-DC converter; a
load electrically connected to the first regulated DC-to-DC
converter to receive the down converted first voltage, wherein the
received down converted first voltage is DC voltage; a second
regulated DC-to-DC converter electrically connected in series to
the first regulated DC-to-DC converter to regulate the down
converted first voltage to a second voltage; and a second energy
source electrically connected to the second regulated DC-to-DC
converter to charge the second energy source using the second
voltage, the second energy source switchably connectable to the
load to provide the load with DC voltage, wherein the second energy
source is connected in series with the second regulated DC-to-DC
converter.
2. The apparatus from claim 1, wherein the first energy source is a
first battery operable at a nominal 800V.
3. The apparatus of claim 1, wherein the second energy source is a
low voltage battery operable at a nominal 48V.
4. The apparatus of claim 1, further comprising a low voltage bus
connecting the first regulated DC-to-DC converter to the load.
5. The apparatus of claim 1, further comprising a switch
electrically connected in parallel with the second regulated
DC-to-DC converter, wherein the second energy source connects to
the load through the switch to supply the load.
6. The apparatus of claim 5, wherein the switch is a MOSFET
switch.
7. The apparatus of claim 5, wherein the switch supplies power to
the load from the second energy source during a failure of the
first regulated DC-to-DC converter.
8. The apparatus of claim 1, wherein the second regulated DC-to-DC
converter is bidirectional, and wherein the second power source
provides power to the load through the second regulated DC-to-DC
converter.
9. The apparatus of claim 8, wherein the power to the load through
the second regulated DC-to-DC converter is supplied in conjunction
with the down converted first voltage.
10. The apparatus of claim 1, further comprising a regulator
electrically connected to the load.
11. The apparatus of claim 1, wherein the second regulated DC-to-DC
converter is a non-isolated buck-boost converter.
12. A method comprising: obtaining a first voltage at an input of a
first regulated DC-to-DC converter from a first energy source, the
first regulated DC-to-DC converter down converting the first
voltage to a second voltage, wherein the first energy source is
connected in series with the first regulated DC-to-DC converter;
supplying the second voltage to a load from the first regulated
DC-to-DC converter via a bus, wherein the second voltage supplied
to the load is DC voltage; supplying the second voltage to a second
regulated DC-to-DC converter, wherein the second regulated DC-to-DC
converter is electrically connected in series to the first
regulated DC-to-DC converter, wherein the second regulated DC-to-DC
converter is operable to provide a charging current to a second
energy source, wherein the second energy source is connected in
series with the second regulated DC-to-DC converter, wherein the
second energy source is switchably connectable to the load to
provide the load with DC voltage.
13. The method of claim 12, wherein the first energy source is a
first battery operable at a nominal 800V and the second energy
source is a second battery operable at a nominal 48V.
14. The method of claim 12, wherein the second regulated DC-to-DC
converter is bidirectional, the method further comprising:
supplying additional power to the load from the second energy
source, the additional power provided through the second regulated
DC-to-DC converter.
15. The method of claim 12, further comprising: detecting a failure
of the first regulated DC-to-DC converter; and activating a switch
electrically connected in parallel with the second regulated
DC-to-DC converter to power the load using the second power
source.
16. An apparatus comprising: a first regulated DC-to-DC converter
with a first input and a second input, the first input of the first
regulated DC-to-DC converter is switchably connected in series to a
first energy source at a first voltage, wherein the first regulated
DC-to-DC converter down converts the first voltage to a second
voltage on a bus; a load electrically connected to the bus, wherein
the load is configured to receive the second voltage, and wherein
the second voltage is DC voltage; a second regulated DC-to-DC
converter electrically connected to the bus; a second power source
electrically connected in series to the second regulated DC-to-DC
converter, the second regulated DC-to-DC converter operable to
charge the second power source or to source current from the second
power source, wherein the second energy source is switchably
connectable to the load to provide the load with DC voltage.
17. The apparatus of claim 16 wherein the second power source is
operable to connect to the bus to supplement power to the bus in
conjunction with the first regulated DC-to-DC converter or to
solely source power on the bus when the first regulated DC-to-DC
converter is not powering the bus.
18. The apparatus of claim 16 wherein: the first energy source
operates in a range of 650-900 volts DC; the second energy source
operates in a range 30-50 volts DC; and the bus operates in a range
of 39-54 volts DC.
19. The apparatus of claim 16 wherein the first regulated DC-to-DC
converter is 4 Kilowatt and the second regulated DC-to-DC converter
is 500 Watts.
20. The apparatus of claim 16 further comprising a regulator
connected between the bus and the load.
Description
TECHNICAL FIELD
Aspects of the present disclosure generally involve a converter
architecture for supplying voltage to a load and a battery.
BACKGROUND
Vehicles, including electric or hybrid vehicles, and other devices
are generally powered by a high voltage battery or other high
energy store. However, such vehicles and devices typically include
components or subsystems, such as battery controllers, motor
controllers, air conditioning systems, and the like, operating at a
relatively lower voltage. Conventionally, a converter down converts
the high voltage powering the vehicle or device to the lower
voltage at which these components and subsystems operate.
SUMMARY
In one implementation, a first regulated DC-to-DC converter is
electrically connected to a first energy source to down convert a
first voltage supplied by the first energy source. The down
converted first voltage may be supplied to a bus, and a load is
electrically connected to the bus and the first regulated DC-to-DC
converter to receive the down converted first voltage. A second
regulated DC-to-DC converter is electrically connected to the bus
to regulate the down converted first voltage. A second power source
is electrically connected to the second regulated DC-to-DC
converter to charge the second power source using a down converted
second voltage, and the second power source is switchably
connectable to the load. Other implementations are described
herein.
BRIEF DESCRIPTION OF THE DRAWINGS
The description will be more fully understood with reference to the
following Figures, which are presented as various implementations
of the disclosure and should not be construed as a complete
recitation of the scope of the disclosure.
FIG. 1 is a diagram illustrating an example load voltage supply
system using a combination of a first regulated direct current to
direct current (DC-to-DC) converter and a second regulated DC-to-DC
converter.
FIG. 2 is a diagram illustrating a second example load voltage
supply system using combination of a first regulated direct current
to direct current (DC-to-DC) converter and a second regulated
DC-to-DC converter
FIG. 2A is a diagram illustrating the system of FIG. 2 configured
in a recovery operation mode.
FIG. 2B is a diagram illustrating the system of FIG. 2 configured
in an open contactor operation mode.
FIG. 2C is a diagram illustrating the system of FIG. 2 configured
in a low power operation mode.
FIG. 2D is a diagram illustrating the system of FIG. 2 configured
in a high power operation mode.
FIG. 2E is a diagram illustrating the system of FIG. 2 configured
in a DC-to-DC failure operation mode.
FIG. 3A is a timing diagram illustrating bus voltage, low voltage
battery voltage and low voltage battery current of the system of
FIG. 2 in various example operational stages.
FIG. 3B is a second timing diagram illustrating bus voltage, low
voltage battery voltage and low voltage battery current of the
system of FIG. 2 in various example operational stages.
FIG. 4 is a flowchart of example operations for providing a load
voltage supply using a combination of a first regulated DC-to-DC
converter for powering a bus and a second regulated converter for
charging or sourcing current from a low voltage battery system.
DETAILED DESCRIPTION
Aspects of the present disclosure involve systems and methods for
supplying voltage to a load. In one aspect, a converter, such as a
direct current-to-direct current ("DC-to-DC") converter, converts a
relatively higher direct current voltage of a high energy store to
a relatively lower direct current voltage utilized by lower voltage
loads. For instance, a vehicle or other device typically includes a
high energy store, such as a high voltage battery, providing motive
current to one or more electric drive motors. The vehicle or device
may also include lower voltage components, including, but not
limited to, electric power steering systems, navigation systems,
dashboard systems, and/or the like, that operate at a lower voltage
than the drive motor(s). The lower voltage components are coupled
to a low voltage bus that is powered with the high energy store by
way of a first regulated DC-to-DC converter. Additionally, the
output of the first regulated DC-to-DC converter provides power to
a second regulated DC-to-DC converter for charging a low voltage
battery, which may nominally operate at the same voltage as the low
voltage bus. The second regulated converter provides a regulated
voltage to a load/source even as load conditions change on the low
voltage battery (or more generally the low voltage bus) and/or
input voltages change due to varying inputs at the first regulated
converter. The low voltage battery may also power the low voltage
components, such as through switchably connecting the low voltage
battery to the low voltage bus, if a failure is experienced at the
first regulated DC-to-DC converter, or if the low voltage bus is
otherwise not powered by the first regulated DC-to-DC
converter.
To begin a detailed description of an example low voltage supply
system 100, reference is made to FIG. 1. In one implementation, the
system 100 includes a first regulated DC-to-DC converter 102
connected to a second regulated DC-DC converter 104 and one or more
loads 108 via the low voltage bus 110. The loads 108 may include
various components and subsystems operating a low voltage relative
to a first energy source 114, which may be, for example, a high
voltage battery.
The first energy source 114 may be connected to the first regulated
DC-to-DC converter 102 through a contactor 112 that is electrically
controlled. It will be appreciated that the first energy source 114
may also provide energy to other systems, including, but not
limited to, an electric motor, that operate at a relatively
different and typically higher voltage than the loads 108.
The first regulated DC-to-DC converter 102 is the primary source
for supplying power to the loads 108 via the low voltage bus 110.
Generally, a DC-to-DC converter may be used to step down voltage,
to step up voltage, or to both step up and down voltage. In one
implementation, the first regulated DC-to-DC converter 102 receives
a high voltage from the first energy source 114 and supplies a
sufficient low voltage to the loads 108. Stated differently, the
first regulated DC-to-DC converter 102 down converts the high
voltage of the first energy source 114 to a lower voltage suitable
for use by the loads 108.
The first regulated DC-to-DC converter 102 may also be a power
source for charging the second energy source 116, such as a low
voltage battery. In one implementation, the second energy source
116 is charged and maintained at a nominal voltage and state of
charge. The second regulated DC-to-DC converter 104 may be disposed
between the first regulated DC-to-DC converter 102 and the second
energy source 116 to supply a regulated voltage and charge current
to the second energy source 116. The second regulated DC-to-DC
converter 104 compensates for any voltage variances of the low
voltage bus 110, which may occur due to different levels of power
drawn by the loads 108. Supplying a controlled, stable voltage to
the second energy source 116 extends a life of the second energy
source 116, assists with charging algorithms, and/or provides other
advantages.
Because the second regulated DC-to-DC converter 104 may be limited
to operating while charging the second energy source 116, the
system may operate more efficiently overall as compared to one with
a regulated converter supplying both the loads and low voltage
battery. The second regulated DC-to-DC converter 104, for example,
may provide a charge current varying between a level for charging
the second energy source 116 from a depleted state to a level
maintaining a charge of the second energy source 116 (e.g., a
trickle charge). The combination of the first regulated DC-to-DC
converter 102 and the second regulated DC-to-DC converter 104 thus
increases the efficiency of the system 100, while providing a
regulated output, when needed, to the second energy source 116.
Stated differently, the first regulated DC-to-DC converter 102
provides efficient power to the loads 108 via the low voltage bus
110, and the second regulated DC-to-DC converter 104 provides
regulated output for charging the second energy source 116.
The second regulated DC-to-DC converter 104 further protects the
second energy source 116 from transients. As the loads 108 switch
on or off or draw varying amounts of power, transient voltages and
spikes may be injected onto the bus 110 and cause damage to the
second energy source 116 if it were connected directly to the bus.
The second regulated DC-to-DC converter 104 is disposed between the
bus 110 and the second energy source 116 to regulate the transient
voltage variations and thus effectively block them from being
absorbed by the second energy source 116.
The first regulated DC-to-DC converter 102 may include high voltage
to low voltage DC-to-DC converter or otherwise be associated with a
transformer, which dielectrically isolates its input from its
output. In some implementations, the first regulated DC-to-DC
converter 102 including a high frequency transformer as an
isolating barrier protects low voltage electronics, such as the
loads 108 and/or the second energy source 116, from high voltage
disturbances that may be transferred from the first energy source
114 or other high voltage systems via the bus 110.
Being connectable to the low voltage bus, the secondary energy
source 116 may provide power to the loads 108 in the event of a
malfunction of the first regulated DC-to-DC converter 102 or when
the first regulated DC-to-DC converter is disabled. Such
malfunctions may include, for example, instances where the first
regulated DC-to-DC converter 102 fails to provide sufficient
voltage to the loads 108, by way of the low voltage bus 110.
Besides disabling (e.g., turning it off) the first regulated
DC-to-DC converter, the first energy source 114 may also not be
coupled to the low voltage bus 110 by opening the contactor 112
during some modes of operation. In one possible implementation, a
switch 106 directs power from the second energy source 116 to the
loads 108 via the low voltage bus 110. The switch 106 may be any
electrical component connecting the second energy source 116 to the
low voltage bus 110, including, but not limited to, a transistor, a
relay, a contactor, and the like. The second regulated DC-to-DC
converter 104 may also be bi-directional and power to the low
voltage bus may be provided through the second regulated DC-to-DC
converter 104. Such may be beneficial when the low voltage battery
voltage differs from a nominal bus voltage.
Turning to FIG. 2, an example load voltage supply and low voltage
battery charging system 200 is shown. The system 200 includes a
first energy source in the form of a high voltage ("HV") battery
214 and a second energy source in the form of a low voltage ("LV")
battery 216. It will be appreciated by those skilled in the art
that the terms "high voltage" and "low voltage" reflect a relative
relationship between a nominal voltage or operating voltage range
of the HV battery 214 and the LV battery 216 and are not intended
to imply any particular voltage or range. In one example, high
voltage refers to various traction battery voltages for driving an
electric motor, and low voltage refers to a voltage or range of
voltages for operating one or more loads 210, such as compressors
(e.g., for air conditioning), fans, entertainment systems, and
other low voltage vehicle systems.
As an example, the HV battery 214 may include a number of low
voltage cells coupled in series and/or parallel to achieve an
overall battery voltage with an operating range of approximately
650-900 volts of direct current ("VDC"). In one implementation, the
LV battery 216 has an operating voltage range that overlaps with an
operating voltage range of a LV bus 218 as configured for the loads
210. For example, the LV battery 216 may have an operating voltage
range of approximately 30-50 VDC, and the LV bus 218 may have an
operating voltage range of approximately 39-54 VDC. In one example,
the HV battery 214 operates at a nominal voltage of approximately
800 VDC, while the LV battery 216 operates at a nominal voltage of
approximately 48 VDC. In other examples, the LV battery 216
operates at a nominal voltage of approximately 24 VDC as a
relatively lower voltage energy source and at a nominal voltage of
approximately 72 VDC as a relatively higher voltage energy source.
In still another example, the HV battery 214 has an operating
voltage range of approximately 270-450 VDC, while the LV battery
216 operates at a voltage range of approximately 39-54 VDC. It will
be appreciated that these voltage values and ranges are exemplary
only and other values and ranges are contemplated.
In one implementation, to provide efficient power to the loads 210
via the LV bus 218 and provide regulated power to the LV battery
216 for charging, the system 200 includes a first regulated
DC-to-DC converter 202 and a second regulated DC-to-DC converter
204. The first regulated DC-to-DC converter, generally speaking,
provides some output depending in part on the input supplied to the
converter. In the case of an isolated converter including a
transformer with primary and secondary windings, for example, the
output voltage will be proportional to the input voltage and depend
on the ratio of primary to secondary windings of the transformer.
That is to say, if a regulated converter receives an input of 800
VDC, it will provide X volts out. But if the regulated converter is
provided 400 VDC, the converter will provide X/2 volts out, instead
of trying to regulate its output to a higher value. So, in the
specific example of an 800 VDC primary energy source, the windings
of the converter may be established to provide an output range of
39-54 VDC based on a high voltage battery range of 650-900 VDC. The
loads receiving power from the low voltage bus thus are those that
can operate in that range. The low voltage battery, however, may
not be able to properly charge if an insufficient input voltage is
provided. For example, a 48 V low voltage battery may not charge
with a 39 VDC input voltage. Hence, the second regulated converter
is able to provide a regulated voltage sufficient for charging the
battery, and able to provide a regulated voltage addressing the
range of possible voltages on the low voltage bus. So, for example,
when charging a 48 V low voltage battery, slightly greater than 48
V may be required and the second regulated DC-to-DC converter may
need to be able to supply that voltage based on low voltage bus
range of 39-54 V DC.
The DC-to-DC converters may be isolated or non-isolated and include
buck converters, boost converters, buck-boost converters, Cuk
converters, charge-pump converters, and/or the like depending on
whether the converted voltage is stepped up, stepped down, both,
and/or inverted. The first regulated DC-to-DC converter 202 may be
a buck converter that reduces the voltage of the HV battery 214 to
a lower voltage value or range for the components connected to the
LV bus 218. The second regulated DC-to-DC converter 204 may also be
a buck type converter to further step-down the voltage across the
LV bus 218 to a voltage for charging or maintaining the LV battery
216, for instance where the operational voltage of the LV battery
216 is lower than the operational voltage of the loads 210. As a
buck converter, the first regulated DC-to-DC converter 202 and the
second regulated DC-to-DC converter 204 may include an inductor, a
transistor and/or a diode configured in a buck arrangement.
In another example where a nominal voltage of the LV battery 216 is
higher than the voltage across the LV bus 218, the second regulated
DC-to-DC converter 204 may be a boost type converter, which
increases the voltage output from the first regulated DC-to-DC
converter 202. In yet another example, the second regulated
DC-to-DC converter 204 is a buck-boost converter. A buck-boost
converter provides buck or boost functionality to decrease or
increase the bus voltage, respectively, depending on the low
voltage bus voltage and the demands of the LV battery 216 and/or
the loads 210 in various operational modes, as discussed in more
detail herein. The second regulated DC-to-DC converter 204
configured as a buck-boost converter further provides bidirectional
functionality, such that power may be directed from the LV bus 218
to the LV battery 216 or directed from the LV battery 216 to the LV
bus 218.
In one particular implementation, the first regulated DC-to-DC
converter 202 is a 4 kW isolated DC-to-DC buck converter, and the
second regulated DC-to-DC converter 204 is a 500 W non-isolated
bidirectional buck-boost converter. The combination of the first
regulated DC-to-DC converter 202 and the second regulated DC-to-DC
converter 204 in this implementation provides the system 200 with a
.eta.=97-98% conversion efficiency.
As described herein, a regulated voltage is provided to the loads
210 via the LV bus 218. In one implementation, one or more of the
loads 210 may utilize a regulated voltage. Thus, a regulator 206
may be operably positioned between the LV bus 218 and such load(s)
210 to provide a regulated voltage. The regulator 206 may also
operate like a regulated converter, compensating the voltage
provided to one or more of the loads 210 where the voltage powering
the load 210 is greater than the low voltage rail on the LV bus
218. Those of ordinary skill will recognize that the regulator 206
may be a discrete component or integrated with one or more of the
loads 210. In the case of a discrete component, the regulator 206
may be shared among the loads 210 or specific to a particular load
210.
A switch 208, such as a metal oxide semiconductor field effect
transistor (MOSFET), may be deployed between the LV battery 216 and
the LV bus 218. The switch 208 selectively supplies power to the
loads 210 from the LV battery 216. For example, the switch 208 may
direct power to the loads 210 from the LV battery 216 when: the HV
battery 214 is unavailable to supply power (e.g., when a HV
contactor 212 is open); the HV battery 214 and/or the first
regulated DC-to-DC converter 202 malfunctions; and, the power
supplied by the HV battery 214 needs to be supplemented.
As can be understood from FIGS. 2A-2E and FIGS. 3A-3B, the system
200 may be deployed in a vehicle and converted to implement various
operation modes. FIG. 2A-2E illustrate a recovery operational mode
220, a contactor open operational mode 230, a low power use
operational mode 240, a high power use operational mode 260, and a
DC-to-DC failure operational mode 280, respectively. The system 200
controls the current flow from the HV battery 214 and to and from
the LV battery 216 during these operational modes using one or more
switches, converters, and/or the like. FIGS. 3A and 3B show timing
diagrams 300 and 350 and illustrate voltages (Vbatt 318 shown in
dashed lines) and currents (Ibatt 322 shown in solid lines) for the
LV battery 216 and voltages (Vbus 320 shown in broken lines) for
the LV bus 218, among other information associated with each of
these operational modes and transitions among the same. FIG. 3B
further illustrates a voltage supply of the LV battery 216 and
across the LV bus 218 during these operational modes, with the LV
battery 216 providing at least some of the voltage supply to the
loads 210 to supplement or replace the HV battery 214 power during
the high power use operational mode. It will be appreciated that
these operational modes and the information and transitions
associated therewith are exemplary only and not intended to be
limiting.
Turning first to FIG. 2A, in one implementation, the system 200 is
configured for the recovery operational mode 220, wherein a charge
state of the LV battery 216 is depleted or otherwise below a
nominal level. For example, the system 200 includes one or more
loads 210, such as an air conditioning system, entertainment
system, navigation system, and/or other vehicle subsystems or
components. If the loads 210 operate for any extended time while
only drawing power from the LV battery 216, the LV battery 216 may
become depleted. In the recovery operational mode 220, the system
200 recharges the LV battery 216 until the charge state reaches the
nominal level.
In one implementation, in the recovery operational mode 220, the HV
contactor 212 is CLOSED, the first regulated DC-to-DC converter 202
and the second regulated DC-to-DC converter 204 are ON, and the
switch 208 is OFF. In this configuration, DC voltage is supplied
from the HV battery 214 to the first regulated DC-to-DC converter
202. The DC voltage is then supplied from the first regulated
DC-to-DC converter 202 to provide a change current in a first
direction 222 to the second regulated DC-to-DC converter 204 to
charge the LV battery 216. The DC voltage is further supplied from
the first regulated DC-to-DC converter 202 along the LV bus 218 to
provide a load current 224 the loads 210.
Referring to FIGS. 2A and 3A together, the timing diagram 300
includes recovery operational mode values 306 associated with the
implementation of the system 200 in the recovery operational mode
220. As shown in FIG. 3A, the Vbatt 318 is in a low charge state
below a nominal level 328 and an operational voltage range 302 for
the LV battery 216. During the recovery operational mode 220, the
Vbatt 318 increases as the charge state is recovered for the LV
battery 216. For example, the Vbatt 318 may increase until the
nominal level 328 is reached. The Vbatt 318 may be monitored until
the charge state is reached.
The Ibatt 322 may be initially low during the recovery operational
mode 220 to reduce a risk of any damage to the LV battery 216 in
the low charge state. In the implementation shown in FIG. 3A, the
Ibatt 322 jumps to a higher current level where it remains until
the LV battery 216 is recharged to the appropriate level. The Ibatt
322 thus corresponds in this case to the Vbatt 318 during the
recovery operational mode 220. Once the charge state is achieved,
the Ibatt 322 decreases to a lower value where power is supplied to
the LV battery 216 during a trickle or maintenance state. The Vbus
320 in the recovery operational mode values 306 depicts a voltage
ramp indicative of no additional loads drawing power from the LV
bus 218 during the recovery operational mode 220. The Vbus 320 may
increase through an upper bound of a voltage range 304 of the LV
bus 218.
Referring to FIGS. 2A and 3B, in another implementation of the
recovery operational mode 220, the HV contact 212 is CLOSED and
both the second regulated DC-to-DC converter 204 and the first
regulated DC-to-DC 202 are ON, thereby directing current from the
LV bus 218 to the LV battery 216. As shown in FIG. 3B, the Vbatt
318 increases at a stable rate towards the nominal level 328, with
the Ibatt 322 varying. Similar to FIG. 3A, the Vbus 320 shows a
ramp up in the recovery operational mode values 306
For a detailed description of the system 200 in the contactor open
operational mode 230, reference is made to FIG. 2B. In one
implementation, the contactor open operational mode 230 includes
the HV contactor 212 in an OPEN position with the first regulated
DC-to-DC converter 202 and second the regulated DC-to-DC converter
204 OFF. As such, no power is supplied to the loads 210 from the HV
battery 214, and the LV battery 216 is not being recharged or
actively maintained with power from the HV battery 214. Stated
differently, no current flow is directed from the HV battery 214 to
the LV battery 216 or the loads 210. The switch 208 may be set to
ON, thereby providing power to the loads 210 from the LV battery
216.
Referring to FIGS. 3A and 3B in view of FIG. 2B, an example
transition sequence from the recovery operational mode 220 to the
contactor open operational mode 230 and an example transition
sequence from the low power use operational mode 240 to the
contactor open operational mode 230 are illustrated with contactor
open operational mode values 314 and 316, respectively.
As discussed above, no current flow is supplied to the LV battery
216 in the contactor open operational mode 230. The Ibatt 322 thus
falls to zero, and depending on a length of time the system 200 is
operating in the contactor open operational mode 230 and/or an
amount of power drawn from the LV battery 216 by the loads 210, the
Vbatt 318 may similarly decrease. In one implementation, the system
200 selects one of the operational modes 220, 240, 260 or 280 based
on a level of the Vbatt 318 following the contactor open
operational mode 230. For example, if the LV battery 216 is too
depleted, the system 200 may select and execute the recovery
operational mode 220 prior to some other operational mode. In
contrast, if the LV battery 216 is operational, albeit at some
state of charge less than 100%, the system 200 may be able to
operate in some other operational mode and recharge or use the LV
battery 216 accordingly.
FIG. 2C illustrates the system 200 in the low power use mode 240
with only nominal operation occurring to reduce power usage. For
example, when the system 200 is deployed in a vehicle, the low
power use mode 240 may correspond to instances where the vehicle is
parked and thus the only loads 210 ON are those pulling low
voltage, such as monitoring memory, sensors, and/or the like.
In one implementation of the low power use mode 240, the HV
contactor 212 is CLOSED, the first regulated DC-to-DC converter 202
and the second regulated DC-to-DC converter 204 are ON, and the
switch 208 is set to OFF. The HV battery 214 thus provides power to
the loads 210 via the LV bus 218. The HV battery 214 further
provides power to maintain the LV battery 216 via the second
regulated DC-to-DC converter 204. As can be understood from FIGS.
3A and 3B in connection with FIG. 2C, in one implementation, the
Ibatt 322 is set an initial level and reduced as the Vbatt 318
reaches and remains at the nominal level 328. At this point, the
Vbatt 318 is provided as a trickle charge in a first direction 242
to maintain the LV battery 216 and in a second direction 244 along
the LV bus 218 to power the loads 210.
Low power use operational mode values 308 demonstrate that the LV
battery 216 and the loads 210 draw little to no power from HV
battery 214 via the LV bus 218 during the low power use mode 240.
As such, the Vbatt 318 and the Vbus 320 have values at the upper
limit of the operational voltage ranges 302 and 304, respectively.
The operational voltage range 302 of the LV battery 216 may be
approximately 39-54 VDC or 30-50 VDC with the upper limit being
approximately 50 VDC, and the operational voltage range 304 of the
LV bus 218 may be approximately 33-56 VDC, with the Vbus 320 being
near 56 VDC during the low power use mode 240.
In one implementation, where the system 200 is transitioning from
the contactor open mode 230 to the low power use mode 240 as shown
with the contactor open operational mode values 314, the Ibatt 322
transitions from zero to a charge current that is sustained until
the LV battery 216 reaches a charged state, at which time the Ibatt
322 drops. Similarly, the Vbatt 318 increases from a level of the
contactor open mode 230 to the nominal level 328. The level of the
contactor open mode 230 may be relatively lower due a gradually
decreasing state of charge and some decrease in the voltage of the
LV battery 26. The voltage supplied across the LV bus 218 supplied
by the first regulated DC-to-DC converter 202 increases the Vbus
320 to the upper limit of the operational voltage range 304.
Referring to FIG. 2D, the system 200 is illustrated in the high
power use operational mode 260 during which the system 200 is
experiencing a high demand from the various low voltage systems,
such as the loads 210 and/or the LV battery 216 to recharge it. The
system 200 may alternatively or additionally have a high demand on
the HV battery 214 by a traction motor or other high voltage
systems.
In one implementation of the high power use operational mode 260,
the HV contactor 212 is CLOSED, the first regulated DC-to-DC
converter 202 and the second regulated DC-to-DC converter 204 are
ON, and the switch 208 is OFF. Where the second regulated DC-to-DC
converter 204 is bidirectional, the voltage across the LV bus 218
may be supplemented with the LV battery 216. As such, power for the
loads 210 is supplied by the HV battery 214 across the LV bus 218
in a first direction 262, which is supplemented by power from the
LV battery 216 across the second regulated DC-to-DC converter 204
in a second direction 264.
Turning to FIG. 3A in the context of FIG. 2D, the high power use
operational mode 260 supplies power to the loads 210 via the LV bus
218, with the Vbus 320 thus being high. In the example case shown
in FIG. 3A, the low voltage battery is initially somewhat
discharged so that besides providing power to the loads, power is
also required to provide a charge current iBatt to the low voltage
battery, which is decreased when some sufficient state of charge is
reached (e.g., 90%).
In one implementation, the second regulated DC-to-DC converter 204
contains one or more sensors configured to sense voltage and
current levels output for the LV battery 216. The sensors of the
second regulated DC-to-DC converter 204 may create current and
voltage loops, which may be used to monitor output impedance for
regulating the voltage and current output by the second regulated
DC-to-DC converter 204. For example, a current sensor can be
located above the second regulated DC-to-DC converter 204 to create
a current loop for monitoring current at an output of the second
regulated DC-to-DC converter 204 to determine whether to increase
the output of the second regulated DC-to-DC converter 204.
Similarly, the second regulated DC-to-DC converter 204 may also
include a voltage sensor located below the second regulated
DC-to-DC converter 204 for voltage regulation. The voltage sensor
creates a voltage loop back into the second regulated DC-to-DC
converter 204 to reduce output impedance by measuring the Vbatt 318
and the Vbus 320. If the Vbatt 318 is greater than the Vbus 320,
the LV battery 216 discharges on the LV bus 218 by way of the
bidirectional second regulated DC-to-DC converter 204 in the second
direction 264. The LV battery 216 thus provides reduced output
impedance at the regulator 206, while maintaining the Vbatt 318
less than or equal to the Vbus 320.
The compensation by the LV battery 216 in the high power use
operational mode 260 is illustrated in FIG. 3B with the high power
use operational mode values 310. In particular, the high power use
operational mode values 310 of FIG. 3B show the Vbatt 318 dropping
as the LV battery 216 directs voltage through the second regulated
DC-to-DC converter 204 to the LV bus 218 as the state of charge of
the LV battery 216 depletes, which may be reflected in the voltage
of the battery. Because the LV battery 216 is supplementing the
voltage across the LV bus 218, the Ibatt 322 is shown as a negative
value meaning it is sourcing current as compared to FIG. 3A where
the battery is being charged during high power mode. With the Vbatt
318 reaching the lower limit of the operational range 304 (e.g., at
or below 50% SOC), the second regulated DC-to-DC converter 204 may
be turned OFF so as to not drain the low voltage battery
further.
For a detailed description of the system 200 operating in the
DC-to-DC failure operational mode 280, reference is made to FIG.
2E. As described herein, the first regulated DC-to-DC converter 202
may malfunction or otherwise become incapable of powering the loads
210. DC-to-DC converter failure can occur for numerous reasons and
be indicated by a reduction in voltage across the LV bus 218 to
below a threshold. During such failures, the LV battery 216 may
power the loads 210 while the LV battery 216 has sufficient charge.
FIGS. 3A and 3B illustrate a scenario where the first regulated
DC-to-DC converter fails and the low voltage battery is at a 90%
SOC and a 50% SOC, respectively. When such a failure occurs, the
low voltage battery is connected to the bus through the switch 208
(ON). As illustrated, iBatt is drawn from the battery and supplies
the loads and the length of time that is able to supply the loads
will depend on the load being drawn as well as the SOC among other
factors. In one implementation of the DC-to-DC failure operational
mode 280, the HV contactor 212 is OPEN, the second regulated
DC-to-DC converter 204 is turned OFF, and the switch 208 is turned
ON to provide power from the LV battery 216 across the LV bus 218
in a first direction 282 and across the switch 208 in a second
direction 284.
For a detailed description of example operations 400 for providing
a load voltage supply using a regulated DC-to-DC converter and a
low voltage battery system, reference is made to FIG. 4. It will be
appreciated that the operations 400 may be implemented using the
system 100 or 200 and in various operation modes, including but not
limited to the operation modes 220, 230, 240, 260, and 280, as well
as other systems and operation modes. The operations 400 may
further be implemented in the context of a vehicle or other device
where power is drawn from a high voltage source and converted to
provide low voltage to one or more loads or low voltage power
sources.
In one implementation, an operation 402 obtains a voltage supplied
by a first power source, such as a high voltage battery, at an
input of a DC-to-DC converter. A contactor, such as a high voltage
contactor, may be disposed between the first power source and the
DC-to-DC converter to control the flow of voltage from the first
power source. The DC-to-DC converter may be unregulated, regulated,
isolated, non-isolated, step-up, step-down, inversion, and/or the
like. For example, the DC-to-DC converter may be a voltage down
converter receiving the voltage supplied by the first power source
at the input and outputting a down converted voltage for one or
more loads, batteries, and/or other systems operating at the down
converted voltage. In another example, the DC-to-DC converter is an
isolated unregulated DC-to-DC converter, providing dielectric
isolation between the input and an output of the DC-to-DC converter
to provide isolation for one or more loads, such as wipers, air
conditioning units, lamp lights, dashboards, and/or the like.
An operation 404 supplies the down converted voltage to one or more
loads via a bus. In addition or alternatively to the operation 404,
an operation 406 supplies the down converted voltage to a second
power source, which may be a low voltage battery. In one
implementation, the operation 406 supplies the down converted
voltage to the second power source via the bus and a regulated
DC-to-DC converter. In one implementation, the voltage across the
bus ranges from approximately 50% to 90% of a voltage of a second
power source, such as a low voltage battery, connected to the bus.
In another implementation, a regulator is connected to the bus to
increase or otherwise regulate the voltage. For example, where the
first power source is a high voltage battery with voltage range of
approximately 650-900 VDC, the bus voltage has a voltage range of
approximately 39-54 VDC (i.e., 50%-90%). As another example, the
first power source is a high voltage battery with voltage range of
approximately 270-450 VDC, and the bus voltage has a voltage range
of approximately 39-54 VDC. With the use of the regulator in the
form of a non-isolated, regulated DC-to-DC converter, the bus may
have a change of voltage range of approximately 33-56 VDC, which
corresponds to approximately 1/8 of the high voltage of the first
power source. Therefore, the voltage on the bus may be higher or
lower than the voltage of the second power source, which a range of
approximately 30-50 VDC.
A second regulated DC-to-DC converter can be operable at a lower
power than the a first regulated DC-to-DC converter used by the
operation 404 to down convert the high voltage provided by the
first power source. For example, the operation 404 may utilize a 4
kW DC-to-DC converter to down convert the voltage from the first
power source, and the operation 406 may utilize a 500 W
non-isolated, regulated DC-to-DC converter to supply power to the
second power source for charging. In some implementations, the
operation 406 turns the second regulated DC-to-DC converter off
when the second power source is not being charged, thereby
increasing efficiency of the system.
In one implementation, operations 408-414 ensure the loads receive
adequate voltage for operation by providing a voltage across the
bus within an operating range of the loads. The operation 408
senses a voltage across the bus and determines whether the bus
voltage is within the operating range of the loads. If the bus
voltage drops below the operational range of the loads, the
operation 410 may identify a malfunction of the first regulated
DC-to-DC converter. The operation 410 may automatically identify an
alternate power source, such as the second power source. Once the
second power source is identified, the operation 410 enables a
switch or bidirectional functionality of the second regulated
DC-to-DC converter to connect the second power source to the bus to
provide power to the loads. Additionally or alternatively, the
operation 410 may use a voltage sensor that triggers the switch to
turn ON where the voltage across the bus is low. Once the switch or
bidirectional functionality of the second regulated DC-to-DC
converter is triggered, the operation 412 supplies voltage to the
loads from the second power source via the bus.
While the present disclosure has been described with reference to
various implementations, it will be understood that these
implementations are illustrative and that the scope of the
disclosure is not limited to them. Many variations, modifications,
additions, and improvements are possible. More generally,
implementations in accordance with the present disclosure have been
described in the context of particular implementations.
Functionality may be separated or combined in blocks differently in
various embodiments of the disclosure or described with different
terminology. These and other variations, modifications, additions,
and improvements may fall within the scope of the disclosure as
defined in the claims that follow.
* * * * *